1. Field of the Invention
The present invention relates to a drawn cup roller bearing or needle roller bearing, more specifically to a full-roller type roller bearing consisting of an annular outer ring or an outer shell, a shaft received therein and a plurality of rollers intervening therebetween, wherein even if the shaft is removed from the internal opening of the annular outer shell, the rollers will not come off from the annular outer ring.
2. Description of the Prior Arts
A drawn cup or needle roller bearing of a conventional type is shown in FIG. 5, wherein 1 is a shaft, 2 is an annular outer ring, for receiving said shaft within the central opening thereof, and 3 is rollers intervening therebetween.
In the conventional roller bearing, the roller 3 is shaped at each of the opposing end portions as a truncated conical configuration, while the annular outer ring 2 has an inwardly projecting roller-retaining edge 5 formed at the free end of each of the inside flanges which are integrally formed at both axial ends of the annular outer ring 2, thus each of the rollers 3 is retained on the inner surface of the internal peripheral sidewall of the annular outer ring 2 with the sloped sidewall 6 of each of the truncated conical-shaped ends 4 of the roller 3 being supported on the inwardly projecting roller-retaining edge 5.
In such a conventional roller bearing having an annular outer ring, however, the axial length of the inwardly projecting roller-retaining edge 5 is so short that to insure a stable retention of rollers thereby, the dimension and shape of the inwardly projecting edge must be accurately controlled in the working thereof, otherwise if the central shaft is removed from the central opening of the annular outer ring and then the rollers are inclined even slightly with the outer ring, it may happen that some of the bearing rollers easily come off from the annular outer ring 2, as indicated by the dotted line in FIG. 6. And when rollers 3 are to be assembled into the annular outer-ring 2, several rollers remaining to be yet assembled must each be forcibly pressed against at least one of the inwardly projecting roller-retaining edges into the roller-retaining, internal peripheral annular space of the annular outer ring so that referring to FIG. 6, the tilted roller depicted by the dotted line can be placed into the position depicted by the solid line. thus, not only end portions of the rollers but also inwardly projecting roller-retaining edges of the outer ring flanges adapted to be contacted with said roller ends are liable to be damaged or broken due to the necessary forcible pressure.
As stated above, in the conventional roller bearing, axial length each of inwardly projecting roller-retaining edges of the outer ring flange is so short that the dimension and shape of the product bearing must be strictly accurate for insuring stable assembling of rollers into the roller-retaining internal peripheral annular space of the annular outer ring. Therefore, the working efficiency involved must be naturally decreased with the production rate of defective bearings being increased. Accordingly, shell-type bearings that should have suitably been manufactured usually on a mass-production basis unexpectedly requires high manufacturing cost.